pwm and normal output on same pin for 16f628a

[baris_akinci]

Hello CCS forum members, sorry maybe this is simple question but I couldn't find a solution while although I searched for days.

I want to make "if condition" program. I mean when a signal comes from RF line, the state will move to the other one. I have done until here but I couldn't achive PWM part I tried both PWM (ON/OFF in us) and CCP module but failed. If I am missing, please let me now.

I use -INT OSC, - same LED for normal output and pwm output

[Ttelmah]

Lots of little comments first:

bytee in the interrupt should be _static_. Otherwise it can potentially be overwritten (in fact the compiler will not, but it is bad programming).

Don't disable INT_RDA in the serial interrupt. Pointless. All interrupts are disabled by the hardware.
It's very inefficient to access the byte each time from an indexed array. It takes typically about 15 instructions to access an array element, but only one or two to access a simple variable. So your code will be smaller and faster, if you just code like:

[baris_akinci]

[Ttelmah]

OK. It should work normally if you disable the PWM.
So:

setup_CCP1(CCP_OFF);

The reason you are having problems, is because you are specifying fast_io, which then means _you_ have to control TRIS. Nowhere are you setting TRIS to '0' for the pin.

[baris_akinci]

[img]
resim yükleme servisi

you can see my project for better understanding. Is there a way to connect all led's to CCP module of 16f628a? because teher is only one output and if I connect all to here, then the LEDs are going short circuit! I think, only one solution is remaining, generating softaware pwm, not CCP module. I tried this by the way but failed!![/b]

[Ttelmah]

You do it the 'other way up'. You have the PWM output drive a common collector transistor to give the _ground_ to all the LED's. Then for any LED you want 'on', you set the output bit that drives it. You can set the intensity by changing the PWM.

Why on earth are you fiddling around with two PIC's. You have spare inputs on one, use them.

[Mike Walne]

In your OP you sound like you're running out of pins.
So why create problems using the same pins twice when you've got spares?

Also why have you got diodes D5-8 in series with the LEDs? The LEDs are diodes!

Depending on the number of brightness levels you want you may be able to use software PWM on all four LEDs.
That way they can have different intensities.

Mike

[asmboy]

Me thinks this is existentially a Proteus/ISIS project. The screen shot doth influence my sentiment. Object reality may be denied us all, including the OP......

[temtronic]

What irks me is the 'messy ' schematic. It should be easy to follow the 'flow' or logic of the product by the layout, which isn't the case here. Horizontal grounds just don't make life easy !
As for the diodes in the LEDs... they do drop the Vout of the PIC by about .7 so you _could_ eliminate the 100r curent limit resistors. While not good practise I have done similar _creative_ hardware in the past.

Jay

[Mike Walne]

Please tell us:-

Is this a REAL HARDWARE project or Proteus/ISIS?

Mike

[baris_akinci]

I think I was misunderstood here. I used two pics because I made Rf communication between 2 pics via RS232 (433 MHz TX-RX device).
this was my mistake because I forget to delete diodes before uploading it. I used them because I tried to use CCP module but all leds were short circuit as below!

[img]
resim yükleme servisi

So, my main question again; I want to make if state LED simulation(sim1,sim2,sim3,..). there are normal outputs (5v) from sim1 to sim5 but for sim6 I want PWM (fading on/off until another signal comes). I tried hardware CCP module but failed, I tried also SPWM but failed again. I need your help at this point.
thank you

[Mike Walne]

Now you're getting me confused.

In your OP you seemed to want ALL the LEDs to connect to the PWM.
Now (in sim6) you only seem to want LED1 to fade.

Please tell us:-

1) How many LEDS do you want to PWM?
2) Do the LEDs all need to PWM in step with each other?
3) Are you wanting to gradually both increase and decrease brightness?
4) How many brightness levels do you want?

AND, most importantly, answer my previous question

Is this REAL hardware or Proteus/ISIS simulation?

Mike

[baris_akinci]

thank you for reply Mike, yes I try to do real hardware but for some test and improvement, I make the ISIS file simple. my last post for sim6() is just to see whether I achieved PWM or not, If I had done, I would have been increased for all LEDs, this was just trying!
for your questions;
all 4 LEDs I want PWM at the same time, yes I want gradually increase/decrease the brighness of LEDs until another signal comes, brightness level depens on how good seemed on eye in real LED.

[Ttelmah]

The ways to do this are:
1) Software PWM.
2) Multiplexing.

With the latter, you connect _all_ the LED's to one PWM output at one end (so their grounds, with a suitable driver transistor), and the other ends to the four chip outputs.
Then you have a choice. If the LED's can all dim together, this is all that is needed. If the LED's want to be different, you multiplex. Sequence is:
Set required power level on PWM for LED1. Turn on it's output. Wait for perhaps 200th second. Then turn off LED1, set level for LED2, turn on LED2. Wait another 200th second. Repeat for LED3, and 4. Then go back to the start. You actually run the LED's with 4* the current you want them to have, but each is only on for 1/4 the time. You can then set the PWM level for each separately. Advantage of this is that the actual PWM is done fast, and it is only the multiplex that needs an interrupt, so something like 200Hz is adequate.

Conversely, software PWM, can be done with your existing hardware, but will need a fast interrupt if you are not to get flickering. The fewer the number of 'levels' you need the easier this is. The code library has basic code for three LED's at:

<http://www.ccsinfo.com/forum/viewtopic.php?t=30139&highlight=software+pwm>

[baris_akinci]

Thank you for reply Ttelmah. what I learned from your refer's topic is that the way to do SPWM is to make many ON/OFF succecivelly in microseconds and we can fading the LEDs by changing their internal period ON/OFF situation's. therefore I made the following code part for sim6()